Chemical Studies of Formosan Cobra (Naja Naja Atra) Venom: Part III. N-Terminal Amino Acid Analysis of Some Purified Protein Components by DNP and DNS Methods

N-Terminal amino acid residues of Fractions IX, X, and XII were reinvestigated by DNP and DNS methods with two-dimensional polyamide thin-layer chromatography. It was found that our previous work¹ had been erroneously concluded. By the present work, it was obvious that all three fractions had Leu as their N-terminal amino acid residues.     

Electrochemistry and photoelectron spectroscopy of oxomolybdenum(V) complexes with phenoxide ligands: effect of para substituents on redox potentials,heterogeneous electron transfer rates,and ionization energies

Complexes of the form (Tp*)MoOCl(p-OC(6)H(4)X) and (Tp*)MoO(p-OC(6)H(4)X)(2) (Tp* = hydrotris(3,5-dimethyl-1-pyrazolyl)borate and X = OEt, OMe, Et, Me, H, F, Cl, Br, I, and CN) were examined by electrochemical techniques and gas-phase photoelectron spectroscopy to probe the effect of the remote substituent (X) on electron-transfer reactions at the oxomolybdenum core. Cyclic voltammetry revealed that all of these neutral Mo(V) compounds undergo a quasireversible one-electron oxidation (Mo(VI)/Mo(V)) and a quasireversible one-electron reduction (Mo(V)/Mo(IV)) at potentials that linearly depend on the electronic influence (Hammett sigma(p) parameter) of X. The first ionization energies for (Tp*)MoO(p-OC(6)H(4)X)(2) (X = OEt, OMe, H, F, and CN) were determined by photoelectron spectroscopy. A nearly linear correlation was found for the Mo(VI)/Mo(V) oxidation potentials in solution and the gas-phase ionization energies. Calculated heterogeneous electron-transfer rate constants show a slight systematic dependence on the substituent.     

Artificial cells in medicine and biotechnology

Since the feasibility of artificial cells was first demonstrated in 1957 [Chang (1, 2)], an increasing number of approaches to their preparation and use have become available. Thus artificial cell membranes can now be formed using a variety of synthetic or biological materials to produce desired variations in their permeability, surface properties, and blood compatibility. Almost any material can be included within artificial cells. These include enzyme systems, cell extracts, biological cells, magnetic materials, isotopes, antigens, antibodies, vaccines, hormones, adsorbents, and others. Since cells are the fundamental units of living organisms, it is not surprising that artificial cells can have a number of possible applications. This is especially so since artificial cells can be “tailor-made” to have very specialized functions. A number of potential applications suggested earlier have now reached a developmental stage appropriate for clinical trial or application. These clinical applications include the use of such cells as a red blood cell substitute, in hemoperfusion, in an artifical kidney or artificial liver, as detoxifiers, in an artificial pancreas, and so on. Artificial red blood cells based on lipid-coated fluorocarbon or crosslinked hemoglobin are being investigated in a number of centers. The principle of the artificial cells is also being used in biotechnology to immobilize enzymes and cells. Developments in biotechnology have also resulted in the use of the principle underlying the artificial cell to help produce interferons and monoclonal antibodies; to create immunosorbents; to develop an artificial pancreas; and to bring enzyme technology usefully into biotechnology and biomedical applications. Artificial cells are also being used as drug delivery systems based on slow release, on magnetic target delivery, on biodegradability, on liposomes, or other approaches. The present status and recent advances will be emphasized in this paper.     

4,4′‐Bipyridyl N,N′‐dioxide–3‐hydroxy‐2‐naphthoic acid (1/2)

4,4′‐Bipyridyl N,N′‐dioxide crystallizes with 3‐hydr­oxy‐2‐naphthoic acid to give a centrosymmetric three‐component adduct, C₁₀H₈N₂O₂·2C₁₁H₈O₃, which is engineered into a two‐dimensional layer structure by two kinds of π–π inter­actions. Weak C—H⋯O inter­actions further link the two‐dimensional structure into a three‐dimensional structure.     

Synthesis and Characteristics of a New Fluorogenic Substrate for Horseradish Peroxidase

N,N′-Dicyanomethyl-o-phenylenediamine was synthesized with a 90% yield by a reaction ofo-phenylenediamine with chloroacetonitrile in triethylamine. Our experimental results showed that it was the effective fluorogenic substrate for horseradish peroxidase (HRP) and hemin. TheK_mfor the HRP system was 48 μM,and that for hemin was 1.3 μM.Properties of the substrate were evaluated from the detection limits of enzymes and H₂O₂. The linear ranges for the determination of HRP and hemin were 21–150 pMand 2–20 nM,respectively. The linear range for the determination of H₂O₂using HRP or hemin was 18–140 and 60–1000 nM,respectively. The structural elucidation of the fluorescent product using NMR and mass spectral techniques was proposed to be 1,2-dihydro-2-imido-imidazo[1,2-a] quinoxaline. Based on the product structure and earlier reports, the possible reaction mechanism of HRP and the substrate was also proposed, i.e., two steps for ring closures, one step of isomerization, and a final step of oxidative dehydrogenation.     

高质量AlPO4-5分子筛单晶的螯合剂法合成与表征

考察了几种螯合剂对AlPO4-5分子筛单晶合成的影响，结果表明，用邻苯二酚，乙酰丙酮，水杨醛为螯合剂可以得到高质量的，尺寸较大的分子筛单晶，其作用机理可能与它们加入到分子筛合成体系中，改变了溶胶中铝的配位数或产生了铝的螯合物有关。     

EPO检测技术的研究进展

促红细胞生成素（EPO）是一种临床上广泛应用的重要药物，也是近年来兴奋剂检测的热点。本文主要从EPO的产生和应用出发，对EPO的结构、特性及其检测方法进行了介绍及评价，重点探讨了竞技体育中EPO的检测技术，并对检测前景作了展望。     

Theoretical study of the unimolecular decomposition mechanisms of energetic TNAD and TNAZ explosives

Calculation methods based on hybrid Density Functional Theory (DFT) with the basis sets of the B3LYP/6‐31+G(d)//B3LYP/4‐31G(d) method and the differential overlap (INDO) program were used to derive reasonable decomposition mechanisms of 1,4,5,8‐tetranitro‐1,4,5,8‐tetraazadecalin (TNAD) and 1,3,3‐trinitroazetidine (TNAZ) explosives. All possible decomposition species and transition states, including intermediates and products, were identified and their corresponding enthalpy of formation and Gibbs free energy of formation were obtained using polyparametric modification equations. INDO bond energy calculation results reveal the weakest bonding site for reference and determine where cleavage can occur easily. This work is concerned mainly with eliminating HONO (cis or trans form). The activation energy for trans‐form HONO elimination is lower than that of cis‐form HONO elimination in the initial steps of both TNAD and TNAZ decomposition, being 18.5 kJ/mol and 33.3 kJ/mol, respectively. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005